1. Field of the Invention
This invention pertains to pulsed gas lasers. More particularly, this invention pertains to means for circulating the gas within a pulsed gas laser.
2. Description of the Prior Art
One method for pumping a pulse discharge gas laser is periodically to discharge electric current through the active volume of gas to excite the gaseous atoms and molecules to the levels appropriate for lasing action. For repetitive operation of the pulse discharge laser, the gas within the active region normally is replaced between discharges. In the typical device, the gas which has been removed from the active region of the laser then passes through a heat exchanger where it is cooled and then, recirculates through the active region. In the prior art, fans have been used to cause the gas to flow in a circulatory manner out of the discharge region through the heat exchanger and back into the discharge region. In applications where extreme reliability of operation of the laser is required, e.g. for operation while in orbit about the earth, a fan with its moving parts, however, is unsuitable. Accordingly, in such applications, means must be found for circulating the gas which do not have moving parts.
U.S. Pat. No. 4,360,922 describes a "Pressure Wave Charged Repetitively Pulsed Gas Laser", invented by Vijay A. Kulkarny, ("Kulkarny"), which invention uses mechanical shutters which are opened and closed in coordination with pressure waves within the gas to cause the gas to circulate within the system. Although the Kulkarny device avoids the use of fans, the mechanical operation of the high speed shutters requires moving parts which impair the reliability of the system.